XML Beautify: indentation screwed by xmlns attribute in self-closing element

XML Beautify:
```



```

https://gchq.github.io/CyberChef/#recipe=XML_Beautify('%5C%5Ct')&input=PGE%2BDQoJCTxiIHhtbG5zPSJmb28iIC8%2BDQo8L2E%2B&ieol=CRLF

Start with the XML Beautify recipe in CyberChef and reproduce the example from the issue, including the xmlns attribute on the self-closing element. Trace the formatter's handling of that element and verify that the resulting indentation matches the intended XML structure.

Written by the indexing model from the issue text.